Citation: Lima, M.S.R.; Gonçalves, C.; Neto, M.D.; Macedo, M.H.; Queiroz, J.L.C.d.; da Silva, V.C.; Costa, I.d.S.; Camillo,C.d.S.; Santos, P.P.d.A.; Lima, A.A.M.; et al. Anti- Inflammatory Protein Isolated from Tamarind Promotes Better Histological Aspects in the Intestine Regardless of the Improvement of Intestinal Permeability in a Preclinical Study of Diet-Induced Obesity. Nutrients 2022, 14, 4669. https://doi.org/10.3390/ nu14214669 Academic Editor: Lindsay Brown Received: 10 October 2022 Accepted: 28 October 2022 Published: 4 November 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). nutrients Article Anti-Inflammatory Protein Isolated from Tamarind Promotes Better Histological Aspects in the Intestine Regardless of the Improvement of Intestinal Permeability in a Preclinical Study of Diet-Induced Obesity Mayara S. R. Lima 1 , Catarina Gonçalves 2 , Mafalda D. Neto 2 , Maria Helena Macedo 2 , Jaluza L. C. de Queiroz 1 , Valéria C. da Silva 3 , Izael de S. Costa 1,4 , Christina da S. Camillo 5 , Pedro Paulo de A. Santos 5 , Aldo A. M. Lima 6 , Lorenzo Pastrana 2 , Bruna L. L. Maciel 7,8 and Ana Heloneida A. Morais 1,7,8, * 1 Postgraduate Program in Biochemistry and Molecular Biology, Biosciences Center, Federal University of Rio Grande do Norte, Natal 59075-000, RN, Brazil 2 International Iberian Nanotechnology Laboratory, 4715-330 Braga, Portugal 3 Postgraduate Program in Development and Technological Innovation in Medicines, Health Sciences Center, Federal University of Rio Grande do Norte, Natal 59075-000, RN, Brazil 4 Nutrition Course, Potiguar University, Natal 59056-000, RN, Brazil 5 Department of Morphology, Federal University of Rio Grande do Norte, Natal 59075-000, RN, Brazil 6 Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza 60430-275, CE, Brazil 7 Postgraduate Program in Nutrition, Health Sciences Center, Federal University of Rio Grande do Norte, Natal 59075-000, RN, Brazil 8 Department of Nutrition, Federal University of Rio Grande do Norte, Natal 59075-000, RN, Brazil * Correspondence: ana.morais@ufrn.br Abstract: Obesity is associated with metabolic and physiological effects in the gut. In this study, we evaluated the anti-inflammatory effect of trypsin inhibitor isolated from tamarind seeds (TTI) in vitro (interaction with lipopolysaccharide (LPS) and inhibitory activity against human neutrophil elastase (HNE)), and using intestinal co-cultures of Caco-2:HT29-MTX cell lines inflamed with TNF- α (50 ng/mL) and a Wistar rat model of diet-induced obesity (n = 15). TTI was administered to animals by gavage (10 days), and the treated group (25 mg/kg/day) was compared to animals without treatment or treated with a nutritionally adequate diet. In the in vitro study, it showed inhibitory activity against HNE (93%). In co-cultures, there was no protection or recovery of the integrity of inflamed cell monolayers treated with TTI (1.0 mg/mL). In animals, TTI led to lower plasma concentrations of TNF-α and IL-6, total leukocytes, fasting glucose, and LDL-c (p < 0.05). The intestines demonstrated a lower degree of chronic enteritis, greater preservation of the submucosa, and greater intestinal wall thickness than the other groups (p = 0.042). Therefore, the better appearance of the intestine not reflected in the intestinal permeability added to the in vitro activity against HNE point to possibilities for new studies and applications related to this activity. Keywords: inflammation; intestinal mucosa; human neutrophil elastase; obesity; tumor necrosis factor-alpha 1. Introduction The worldwide prevalence of obesity has been increasing over the last few years at epidemic proportions. According to the World Obesity Federation [1], by 2025, more than 16% of the world’s adult population will be obese. Obesity is a preventable condition caused by an energy imbalance between consumed and expended calories, mainly due to physical inactivity and increased intake of energy-dense foods, high in fat and sugar [2,3]. These excess calories can cause chronic low-grade inflammation, as adipocyte hypertrophy Nutrients 2022, 14, 4669. https://doi.org/10.3390/nu14214669 https://www.mdpi.com/journal/nutrients